1. Patients with histologically proven malignant glioma who have progressive disease following standard treatment will be eligible for this protocol. Malignant glioma include glioblastoma multiforme (GBM), anaplastic astrocytoma (AA), anaplastic oligodendroglioma (AO), anaplastic mixed oligoastrocytoma (AMO), or malignant glioma NOS (not otherwise specified). Additionally, patients with primitive neuroectodermal tumors (PNETs) of the central nervous system, progressive low-grade gliomas and radiographically diagnosed brain stem gliomas will be eligible.